Oh la la la! Sign up for an lala account and create your own online playlist (which you can access from anywhere). You can then play any song or album once for free, purchase a web song for 10 cents (with unlimited online plays), or download the MP3 version for 79 cents.

I love the site for its networking element — you can connect with friends, find folks with similar musical tastes and gift songs. I find the catalog of available tunes incredibly comprehensive and the site easy to navigate.

8Tracks

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This site allows you to upload MP3s online and create your own playlists in a community-type website, which means you can enjoy files from your home computer while at work. You can also enjoy new tunes by checking other people's playlists, and easily share your playlist with friends and family.

The site that started it all, Muxtape, became unavailable last August after legal disputes with the RIAA, but thankfully an impressive site called 8tracks has debuted a similar (if yet better) online music service.

Grooveshark and Grooveshark Lite

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Grooveshark lets you upload your music for easy access anywhere that there's an Internet connection. Plus you can share, rate, and review music all over the web from your Grooveshark profile page. Think MySpace, but just for your music library, that's totally fun to use.

And Grooveshark Lite? Well, it allows you to browse through millions of songs worldwide, make your own custom playlists, and get this — listen to them in their entirety without interruption. GSLite can even create playlists for you, which is a great way to discover new music. Just imagine browsing the world's iTunes libraries, and you'll get the idea. I'm so in love, I can hardly stand it.

Pandora

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Perhaps the staple Internet radio destination, Pandora offers Internet radio in an easy-to-use interface. Type in your favorite songs and artists and Pandora will create customized playlists for you. You can interact with friends, rate songs and explore artists. You can even play it on your BlackBerry or iPhone if your work doesn't allow streaming radio.

last.fm

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I adore last.fm because it "scrobbles" your playlists, which means every song you listen to with Last.fm becomes part of your music profile. In essence, the site keeps track of what music you listen to, and then produces a large number of features personalized to you.

After that you can create personal music charts automatically, find your "musical soul mates," generate a personal radio station and see what your friends are listening to. The site is free.